/* ESPIDFORTH project site
   Palette: warm-neutral paper, near-black ink, deep pine accent (the Forth "ok").
   Type:    Archivo (display) / Source Serif 4 (prose) / JetBrains Mono (code) */

:root {
  --bg:          #f3f4f1;
  --surface:     #ffffff;
  --surface-2:   #e7e9e4;
  --ink:         #14171a;
  --muted:       #5d6560;
  --rule:        #d3d7d0;
  --accent:      #1f6b4d;
  --accent-soft: #e2eee8;
  --warn:        #8a5a15;
  --warn-soft:   #f5ecda;
  --crit:        #9e2b23;
  --crit-soft:   #f6e4e2;

  --f-display: "Archivo", "Helvetica Neue", Arial, sans-serif;
  --f-body:    "Source Serif 4", Georgia, "Times New Roman", serif;
  --f-mono:    "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg:          #0f1311;
    --surface:     #161b18;
    --surface-2:   #1e2521;
    --ink:         #e3e7e3;
    --muted:       #8d968f;
    --rule:        #282f2b;
    --accent:      #5fc496;
    --accent-soft: #16241d;
    --warn:        #d6ab5c;
    --warn-soft:   #251f12;
    --crit:        #e3776d;
    --crit-soft:   #2a1917;
  }
}
:root[data-theme="dark"] {
  --bg:          #0f1311;
  --surface:     #161b18;
  --surface-2:   #1e2521;
  --ink:         #e3e7e3;
  --muted:       #8d968f;
  --rule:        #282f2b;
  --accent:      #5fc496;
  --accent-soft: #16241d;
  --warn:        #d6ab5c;
  --warn-soft:   #251f12;
  --crit:        #e3776d;
  --crit-soft:   #2a1917;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 72px; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--f-body);
  font-size: 17px;
  line-height: 1.65;
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: 820px; margin: 0 auto; padding-left: 20px; padding-right: 20px; }

/* ---------- nav ---------- */
nav.top {
  position: sticky; top: 0; z-index: 20;
  background: var(--bg);
  border-bottom: 1px solid var(--rule);
}
nav.top .wrap {
  display: flex; align-items: center; gap: 8px 22px;
  flex-wrap: wrap;
  padding-block: 12px;
}
nav.top .brand {
  font-family: var(--f-display);
  font-weight: 700; font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--ink); text-decoration: none;
  margin-right: auto;
}
nav.top .brand .dot { color: var(--accent); }
nav.top a.lnk {
  font-family: var(--f-display);
  font-size: 13.5px; font-weight: 500;
  color: var(--muted); text-decoration: none;
}
nav.top a.lnk:hover, nav.top a.lnk[aria-current="page"] { color: var(--accent); }

/* ---------- hero ---------- */
header.hero { padding-block: 56px 34px; border-bottom: 2px solid var(--ink); }
.eyebrow {
  font-family: var(--f-mono);
  font-size: 11.5px; font-weight: 500;
  letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 14px;
}
h1 {
  font-family: var(--f-display);
  font-weight: 700;
  font-size: clamp(34px, 6.6vw, 52px);
  line-height: 1.04; letter-spacing: -0.02em;
  margin: 0 0 16px; text-wrap: balance;
}
.standfirst { font-size: 20px; color: var(--muted); margin: 0 0 24px; max-width: 60ch; }

.cta-row { display: flex; flex-wrap: wrap; gap: 10px 14px; align-items: center; }
.btn {
  font-family: var(--f-display); font-weight: 600; font-size: 14.5px;
  text-decoration: none;
  padding: 9px 18px; border-radius: 3px;
  border: 1.5px solid var(--accent);
  display: inline-block;
}
.btn.solid { background: var(--accent); color: var(--bg); }
.btn.ghost { color: var(--accent); }
.btn:hover { opacity: .85; }

/* ---------- sections ---------- */
section { padding-block: 46px 0; }
h2 {
  font-family: var(--f-display); font-weight: 700;
  font-size: 29px; letter-spacing: -0.012em;
  margin: 0 0 8px; text-wrap: balance;
}
h3 {
  font-family: var(--f-display); font-weight: 600;
  font-size: 19.5px; margin: 30px 0 8px; text-wrap: balance;
}
h4 {
  font-family: var(--f-display); font-weight: 600;
  font-size: 13px; letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--muted); margin: 22px 0 7px;
}
p { max-width: 68ch; }
.lede { color: var(--muted); font-size: 18px; margin: 0 0 6px; max-width: 64ch; }

a { color: var(--accent); text-underline-offset: 2px; }
a:focus-visible, .btn:focus-visible, summary:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 2px;
}

code, .mono { font-family: var(--f-mono); }
p code, li code, td code, dd code, h3 code, h4 code {
  font-size: 0.84em; background: var(--surface-2);
  padding: 1px 5px; border-radius: 3px; word-break: break-word;
}

ul.plain { padding-left: 20px; }
ul.plain li { margin-bottom: 7px; max-width: 64ch; }

/* ---------- code blocks ---------- */
pre {
  background: var(--surface-2);
  border-left: 3px solid var(--rule);
  font-family: var(--f-mono);
  font-size: 13px; line-height: 1.62;
  padding: 13px 16px; margin: 13px 0;
  overflow-x: auto; color: var(--ink);
  tab-size: 4;
}
pre.repl { border-left-color: var(--accent); }
pre .p  { color: var(--accent); font-weight: 500; }   /* prompt */
pre .c  { color: var(--muted); }                       /* comment */
pre .o  { color: var(--muted); font-style: italic; }   /* output */
pre .e  { color: var(--crit); }                        /* error */

.filename {
  font-family: var(--f-mono); font-size: 11.5px;
  color: var(--muted); letter-spacing: 0.04em;
  margin: 16px 0 -6px;
}

/* ---------- tables ---------- */
.tw { overflow-x: auto; margin: 18px 0 6px; }
table { border-collapse: collapse; width: 100%; font-size: 15px; min-width: 560px; }
th {
  font-family: var(--f-display); font-weight: 600;
  font-size: 12.5px; letter-spacing: 0.05em; text-transform: uppercase;
  text-align: left; color: var(--muted);
  border-bottom: 1.5px solid var(--ink);
  padding: 0 14px 8px 0; vertical-align: bottom;
}
th.hi { color: var(--accent); }
td { padding: 10px 14px 10px 0; border-bottom: 1px solid var(--rule); vertical-align: top; }
td:last-child, th:last-child { padding-right: 0; }
td.hi { background: var(--accent-soft); padding-left: 10px; }
th.hi { padding-left: 10px; }
.num { font-variant-numeric: tabular-nums; white-space: nowrap; }

/* ---------- callouts ---------- */
.note, .warnbox {
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  padding: 14px 18px; margin: 18px 0;
  font-size: 16px;
}
.warnbox { border-left-color: var(--warn); background: var(--warn-soft); }
.note p, .warnbox p { margin: 0; max-width: 62ch; }
.note p + p, .warnbox p + p { margin-top: 9px; }
.note b, .warnbox b { font-family: var(--f-display); }

/* ---------- use-case / reference cards ---------- */
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(270px, 1fr)); gap: 2px; margin-top: 20px; }
.uc { background: var(--surface); padding: 18px 20px 20px; border-left: 3px solid var(--rule); }
.uc h3 { margin: 0 0 6px; font-size: 17px; }
.uc p { margin: 0; font-size: 15.5px; color: var(--muted); max-width: none; }

dl.refs { margin: 18px 0 0; }
dl.refs dt { font-family: var(--f-display); font-weight: 600; font-size: 16.5px; margin-top: 18px; }
dl.refs dd { margin: 2px 0 0; color: var(--muted); font-size: 15.5px; max-width: 64ch; }
dl.refs dd .u { font-family: var(--f-mono); font-size: 12.5px; word-break: break-all; }

/* ---------- tutorial layout ---------- */
.tut { border-top: 1px solid var(--rule); padding-block: 30px 6px; }
.tut-head { display: grid; grid-template-columns: 54px 1fr; gap: 0 18px; align-items: start; }
.tut-n {
  font-family: var(--f-mono); font-size: 13px; font-weight: 600;
  color: var(--accent); padding-top: 7px; font-variant-numeric: tabular-nums;
}
.tut-head h3 { margin: 0 0 4px; font-size: 22px; }
.tut-meta { font-family: var(--f-mono); font-size: 11.5px; color: var(--muted); letter-spacing: 0.04em; }
.tut-body { padding-left: 72px; }
.tut-body > :first-child { margin-top: 12px; }

.badge {
  display: inline-block; font-family: var(--f-mono);
  font-size: 10px; font-weight: 500; letter-spacing: 0.08em; text-transform: uppercase;
  padding: 2px 7px; border-radius: 2px; margin-left: 8px; vertical-align: 2px; white-space: nowrap;
}
.b-runs { background: var(--accent-soft); color: var(--accent); }
.b-ffi  { background: var(--warn-soft); color: var(--warn); }

.toc { background: var(--surface); padding: 18px 22px; margin-top: 22px; border-left: 3px solid var(--accent); }
.toc ol { margin: 0; padding-left: 22px; font-size: 15.5px; }
.toc li { margin-bottom: 5px; }
.toc a { text-decoration: none; }
.toc a:hover { text-decoration: underline; }

footer {
  margin-top: 60px; padding-block: 22px 60px;
  border-top: 1px solid var(--rule);
  font-family: var(--f-mono); font-size: 12px; color: var(--muted);
}
footer p { max-width: 70ch; margin: 0 0 8px; }

@media (max-width: 620px) {
  body { font-size: 16.5px; }
  .tut-head { grid-template-columns: 1fr; gap: 0; }
  .tut-n { padding-top: 0; margin-bottom: 3px; }
  .tut-body { padding-left: 0; }
  header.hero { padding-block: 38px 28px; }
}